The perimeter of the rectangle is 140mm. The width of the rectangle is 2/5 of its length. Find the area of the rectangle.

The perimeter P of the rectangle is 140 millimeters.
The width b of a rectangle is 2/5 of its length a.

Let the length a of the rectangle be x millimeters.
Then the width b of the quadrangle will be 2 / 5x millimeters.
Let’s make the equation:
x + x + 2 / 5x + 2 / 5x = 140;
14 / 5x = 140;
x = 140: 14/5;
x = 50.
The length a of the figure is 50 millimeters.
Find the width b:
b = 50 * 2/5 = 20 millimeters.
Let’s calculate the area of the rectangle:
S = a * b = 50 * 20 = 1000 mm2.
Answer: S = 1000 mm2.